Cloudflare Email Service Skill
Guides agents through implementing transactional email sending, receiving, and routing on Cloudflare.
The document discloses API tokens, domain verification, sensitive email content, recipient verification, suppression lists, restricted sender bindings, and a human-review pattern, while warning against hardcoded credentials. However, sending, forwarding, and suppression changes lack explicit user confirmation, a least-privilege permission matrix, and rollback procedures; examples also expose full recipient, subject, and event data. The deduction for incomplete confirmation, isolation, and recovery yields 14/25.
The skill clearly separates Workers bindings, REST, routing, agents, and error codes, and documents several failure responses. However, there are no committed tests or reproducible execution records for key paths; several behaviors and fields depend on external documentation, and claims such as forwarding failing silently are not internally verified. Edge-case coverage is limited. Static calibration supports 8/20.
The skill identifies concrete scenarios for sending, receiving, agents, CLI/MCP, and deliverability, and distinguishes transactional from marketing email. However, its trigger scope is broad, inputs and outputs are not systematically specified, non-fit cases are incomplete, Chinese-language guidance is absent, and mainland-China reachability is not addressed. Core retrieval depends on Cloudflare, npm, and GitHub services that may be difficult to reach from mainland China. Score: 10/15.
The main document uses progressive disclosure through scenario-specific references and includes setup notes, examples, limits, and common mistakes. The repository supplies an Apache-2.0 license, and the skill warns that its content may become stale and directs users to source material. It lacks skill-level versioning, a changelog, named maintenance ownership, and a clear update path, with incomplete dependency governance and troubleshooting coverage. Score: 9/15.
Examples cover Workers, REST, routing, attachments, deliverability monitoring, and Agent email handling, so accurate content could provide a directly usable implementation starting point. Static review cannot confirm that commands, API fields, or examples execute, and there is no evidence comparing the result with manual alternatives. Static calibration therefore limits the score to 7/15.
The skill names auditable Cloudflare documentation, the REST API specification, Workers types, and the Agents SDK as source-of-truth materials, and repeatedly instructs retrieval from originals. However, it provides no committed tests, CI results covering the skill, or independent reproduction records; evidence is primarily author-written guidance and examples. Score: 4/10.
- Sending and forwarding email have real external side effects; execution should require confirmation and clearly scope recipients, senders, credential permissions, and recovery options.
- Do not transfer the remote-development configuration directly to production or real recipients; the document states that remote=true actually sends email.
- Cloudflare API fields, Wrangler commands, error codes, and GraphQL schemas may change; verify them against the original specifications before implementation.
- Inbound mail, subjects, bodies, attachments, and analytics events require data minimization, access control, and redaction.
What does this skill do, and when should you use it?
This skill covers Cloudflare Email Service, including Email Sending and Email Routing. It guides developers through sending transactional email with a Workers binding or REST API, as well as processing inbound mail. The material includes Agents SDK email handling, Wrangler setup, MCP tools, and SPF, DKIM, and DMARC guidance. It is retrieval-first because the service launched in 2025 and is still evolving quickly.
It checks whether a domain is enabled for Email Sending, looks for a send_email binding in wrangler.jsonc, and identifies postal-mime as a receiving and parsing dependency. It provides implementation paths and examples for Workers bindings, the REST API, Email Routing, the Agents SDK, Wrangler CLI, and MCP. It also covers HTML and plain-text messages, attachments, custom headers, forwarding, replying, and common configuration mistakes.
- A developer adding welcome, notification, or registration emails to a Cloudflare Worker.
- A developer building a Cloudflare Agents SDK agent that receives email and handles it with onEmail() or replyToEmail().
- A developer sending mail from an external Node.js, Python, or Go application through the Cloudflare Email Sending REST API.
- A team configuring Email Sending or Email Routing with Wrangler or the Cloudflare Dashboard.
- A developer troubleshooting SPF, DKIM, DMARC, bounces, suppressions, or spam-folder placement.
What are this skill's strengths and limitations?
- Covers Workers bindings, the REST API, Email Routing, and Agents SDK email workflows.
- Includes directly usable wrangler.jsonc, TypeScript, and REST API examples.
- Clearly distinguishes Workers and REST API field names and failure modes.
- Includes setup, deliverability, and SPF, DKIM, and DMARC guidance.
- It explicitly requires retrieval from official sources, so it should not be treated as permanently current product documentation.
- It is for transactional email, not newsletters, marketing campaigns, or bulk promotional sending.
- The source provides no test suite, version pinning, or complete standalone installation procedure.
- Some workflows require Cloudflare domain configuration, Wrangler, network access, or MCP tools.
How do you install this skill?
The skill is part of the cloudflare/skills collection. An Agent Skills-compatible client can install the collection with npx skills add https://github.com/cloudflare/skills; alternatively, clone the repository and copy skills/cloudflare-email-service into the client’s skill directory. The README lists directories for Claude Code, Cursor, OpenCode, OpenAI Codex, and Pi, but does not document a separate installation command for this skill alone.
How do you use this skill?
Ask a supported coding agent for a concrete task such as “Add email to my Cloudflare Worker” or “Configure Cloudflare Email Routing and process inbound mail.” Before sending, verify the domain and binding; run npx wrangler email sending list, and if needed run npx wrangler email sending enable yourdomain.com.
How does this skill compare with similar options?
The skill distinguishes Cloudflare Email Service from dedicated marketing email platforms: Cloudflare Email Service is positioned for transactional email, while newsletters and marketing campaigns should use a dedicated marketing platform.